Getting Started with Calibre

Getting to know new tools can feel daunting, which is why we created this guide to help you get started and be successful in establishing a site speed monitoring system. You can always explore all features or contact our friendly support team if you have any questions.

Step 1: Add your Sites to Calibre

To add a Site, choose from 17 global test locations, add a name, provide a URL to be tested, set a testing schedule and assign it to a Team. Calibre allows you to check unlimited sites and pages, without any extra cost.

After creating the Site, you can configure its settings: where it’s tested from, how often, under which Test Profiles, add additional pages and more.

The initial test runs six consecutive Snapshots to provide the most reliable results. We will email you when results are ready.

Step 2: Configure test environments

After adding Sites and pages to track, it’s time to choose the conditions for testing. Test Profiles allow you to set up a combination of testing scenarios that cover a wide range of user experiences.

You can emulate devices, network speeds, authenticate into your applications, turn off ads or specific third party vendors. Calibre will automatically create three baseline Test Profiles for you:

• Chrome Desktop with a Cable connection
• Motorola Moto G4 with a regular 3G connection
• iPhone with a 4G LTE connection

These three Test Profiles show an accurate portrayal of the speed spectrum, based on global averages. Mix and match settings to create comprehensive user testing scenarios relevant to your audience. We recommend turning off ads and testing without third parties.

Step 3: Set Performance Budgets

Budgets are a great way of making sure that when the speed of your Sites deteriorates, you are instantly notified and can act on regressions. Set budgets against any metric available in Calibre and apply them to specific pages and Test Profiles.

You can be notified when a budget is met, exceeded or at risk in two ways: through email or Slack alert posted to a chosen channel.

We recommend starting with setting budgets against several metrics that describe user experience most accurately, such as:

• Largest Contentful Paint
• Cumulative Layout Shift
• Total Blocking Time
• First Contentful Paint
• Total JavaScript Transferred
• Time to First Byte
• Total Third Party Code Transferred

It’s also worth keeping an eye on the Lighthouse Performance Score as it provides a more high-level view of speed, that might be helpful when communicating with project managers, stakeholders and across different teams.

Step 4: Set up Pull Request Reviews

A majority of speed regressions are preventable using pre-production monitoring. With Pull Request Reviews, you’re will see the speed impact of your work before it affects your customers.

Each review will showcase changes in critical, Core Web Vitals metrics: Largest Contentful Paint, Cumulative Layout Shift and Total Blocking Time. It will also highlight the most significant changes in metrics and budgets on a per-page basis.

A comprehensive comparison of your production (or staging) environment and the changes made in the Pull Request will be posted as a comment, accessible to anyone using GitHub. You can enable Pull Request Reviews for any selected Site.

To use Pull Request Reviews, you need to be using GitHub and one of the supported deployment methods, such as Vercel, Netlify, Heroku or GitHub deployment statuses.

Step 5: View the results

There are several ways to view speed data in Calibre. First one is the Pulse page, showcasing historical metric data trends across Test Profiles, including markers for when deploys happened. Metric graphs can be reordered and explored to investigate 6, 3, 1 month and 7-day averages.

Snapshot Overview provides the most speed information:

• critical speed metrics (color-coded based on good, need improvement or poor readings)
• a render timeline
• a JavaScript Main Thread Execution Timeline
• assets transferred by type graph
• request table

You can view a render video of your Site and inspect the stages of rendering in a timeline, which helps with grading what your users experience. With the Main Thread Execution Timeline, it’s possible to pinpoint long-running and blocking JavaScript tasks. Lastly, assets and requests can be inspected in great detail to find speed bottlenecks.

Performance, SEO, Best Practices, Accessibility and PWA tabs provide information about passed and failed Lighthouse audits, highlighting opportunities for improvement.

The Third Party tab provides insight into how external scripts and tools contribute to worsening your site speed. You can quickly analyse which third party vendors contribute most transfer size and main thread execution time to your overall scores.

Step 6: Organise work with Teams

Everyone has different needs and preferences for organising their work. Create Teams to assign people to work on specific Sites. Divide based on projects, areas of the business or add Teams for personal experimentation:

You can control access levels and avoid information overload. Teams make it easy to collaborate and focus on what’s important to you.

Once you have completed these steps, continue your journey with Calibre by discovering all features or reaching out to our technical support team for help in establishing your speed strategy.